Concrete pumping system



May 14, 1935. c. F. BALL CONCRETE PUMPING SYSTEM Filed April 6, 1935 0VIII/14%? VIJVIIAr/ll/ Patented May 14, 1935 I UNITED STATES PATENTOFFICE 2,001,661 CONCRETE PUIWPING SYSTEM Charles F. Ball, Milwaukee,Wis., asslgnor to Chain Belt Company, Milwaukee, Wla, a corporation ofWisconsin Application April 6 ,1933, Serial No. 664,827 3 Claims. (or.103-224) This invention relates to pumping systems, and ing deviceslocated in the usual position on or immore particularly to one includinga. recently demediately adjacent the pump, the back pressure velopedtype of pressure pump especially adapted set up by such damping devicesis sufilcient to for handling concrete and plastic mixtures having forceportions of the mixture back through e 5 characteristics similarthereto, and has for its valves while thus open, resulting in whatistermed 5 principal object to improve the operation and black-slip andlowering the efficiency of the efliciency of such systems. system. Inorder that the precise nature of the inven- On the other hand, I havefound that if the tion maybe clearly understood, it may be saidpulsation damping device be 50 located t that the pressure pumps abovereferred to are communicate with the discharge line atadistance 10usually, although not necessarily, single cylinder of ay from 5 t0 100feet from the D pmachines having single acting pistons, i. e. pisp ndentp t Consistency of the mixture tons which suck the plastic mixture intothe cyling handled and other factors-the inertia of the inder upon onestroke and force it therefrom up n Portion of the mixture in the Conduitbetween the 1 the succeeding stroke. Because of the size of dampi gdevice a d t e pu together w the certain of the constituents of thecommonly used friction between the mixture and the Walls of the concretemixtures-the large aggregate may range conduit, will be sufiicient toovercome the back from one quarter inch up to two and one-half p e Setup by the damping device and p or three inches ingreatest diimension-thevalves t reverse m v of the m u r u of these pumps are not designed toseat tightly so the Valves during the intervals WheI1 they are 20 as tocompletely close off the passages controlled Simultaneously fully nearlyfully Op thereby, but are moved in proper seque ce from The inventiontherefore resides specifically in their fully open positions topositions in which l i the i dome r h r pul ti n ampin they partiallyrestrict but do not fully close their d v ce a a Point in the dischargeconduit respective passages, advantage being taken of the eiehtlyremoved from the p that the inertia 25 peculiar packing 0r stowingproperty of such and friction of that portion of the mixture lyingmixtures at such restrictions to substantially comwithin the conduitbetween the pump and the pletely prevent movement of the mixture in adidampin device s great enough to resist the b rection opposite to thatin which it, is being pressure exerted by the lattertothe extentnecespumped. sary to prevent the objectionable back-slip of 30 Thesepumps usually operate at from 40 t 50 the. mixture through thesimultaneously open pressure strokes per minute, there of course being av all as Will be more fully hereinafter an equal number of suctionstrokes during which scribed and part c y Pointed Out in the -D- theoutlet valve is in its most restricting position pended claims.

and the mixture in the discharge conduit beyond Referring to theaccompanying drawing, form- 35 said valve is not being pushed forwardly.This ing a part of this specification, in which like refresults in anintermittent forward movement of erence characters designate like partsin all the the mixture in the discharge pipe, and a pulsatviews:-

ing discharge therefrom. Under many conditions Figure l is a more orless diagrammatic side such pulsating discharge is objectionable, and itelevational view ofa concrete pump of the type 40 has been proposed tosmooth out and substanabove mentioned, a discharge conduit therefore,tially eliminate the pulsations-through the use of and a pulsationdamping device in the form of air chambers or other pulsation dampingdevices, an air dome communicating therewith and 10- as is commonpractice in liquid pumps. cated in accordance'with the presentinvention:

Notwithstanding the fact that the valves of Fig. 2 is an enlargedfragmentary sectional 45 these pumps are substantially simultaneouslyacview through the inlet and outlet valves of the tuated-usually by camsto insure positive and pump illustrated in Fig. 1, showing the positionsrelatively rapid movement from one position to they occupy during thepressure stroke of the the otherthere is a. certain interval during eachpiston;

valve movement when both valves may be com- Fig. 3 is a view similar toFig. 2, but illustrating b0 pletely or nearly completely open, and thelength the valves in the course of their movements at of this intervalmay in some instance be increased the end of the pressure stroke of thepiston, and if one of the valves has a lead over the other. showing howthey may simultaneously occupy Because of this condition, it has beenfound that nearly fully open positions; and

with the use of air domes or other pulsation damp- Fig. 4 is a viewsimilar to Fig. 2, of a somewhat b5 modiiiodformofpumminwhichasinglevalve controls both the inlet and the outlet passages.

In the said drawing, Ill indicates generally aconcretepumphavingacylinder ll providedwith aninletpassage l2andanoutletpassage II. The inlet passage i2 communicates with a valvehousing it inwhich is mounted a plug member II, constituting the inletvalve, and which is provided with a passage ll adapted in the openposition of the valve (indicated in broken lines in Fig. 2) to alinewith the passages ll of the valve housing ll. The valve plug II isarrangedto be oscillated from its restrictive full-line positionillustrated in Fig. 2 to its open broken-line position and back again bymeans of a valve arm II, a connecting rod assembly ll, anda rocker arm20, which is actuated by suitable cams within a housing 2|. A feedhopper 22 surmounts the valve housing I4 and receives the plasticconcrete from any appropriate mixer.

In similar manner the outlet passage l3 communicates with a'valvehousing 25 in which is mounted the outlet valve plug 20, having thepassage 21 arranged to aline with the passages I. of the housing 25, andto be moved back and forth between its fulland broken-line positions,illustrated in Fig. 2, by an arm 2!, connecting rod ll,

and a rocker arm and cams located on the far side of the machine. Thedischarge pipe or con-' duit II is connected to the outlet valve housing25, and at a point suillciently removed from the pump may be providedwith a'fitting 32, upon which may be mounted the air dome or otherpulsation damping device I3.

During the pressure stroke of the pump piston II, the valves l6 and 28occupy the positions shown in Fig. 2, with the inlet valve II in itsmost restrictive position, and the outlet valve 26 in its fully openposition. As the piston 34 reaches the end of its pressure stroke, asindicated in Fig. 3, the cams actuate the respective rocker arms such as28, the'connecting rods I9 and 30, and the valve arms II and 29, to movethe valve plugs II and 26 in a clockwise direction from the full-linepositions of Fig. 2 to the broken line positions shown therein. At sometime during this operation the valves may occupy substantially thepositions illustrated in Fig. 3, in which it will be observed thatneither valve imposes much restriction in the passages controlled by it;and it is during the interval that the valves are approaching andleaving these positions that back-slip" may occur if the pulsationdamper be located in its usual place on or immediately adjacent thepump. On the other hand, if it be located a suitable distance from thepump, as indicated in Fig. l, the inertia of the mixture within thatportion of the conduit 3| between the-outlet valve 26 and fitting 32will be sufllcient to resist the pressure built up in the air dome 33,and which would tend to force the mixture back toward the pump on thesuction stroke of the piston.

Obviously, the same condition permitting of "back-slip will be presentin the modified type of pump illustrated in Fig. 4, wherein a singlevalve 35 controls both the inlet passage l2 and the outlet passage l3,since as the said valve moves from the full line position to the brokenline position shown therein,and vice versa, the two passages may besimultaneously open a sufficient time to allow the objectionablebackward movement of the material being pumped. The present invention istherefore of value in connection with this form of pump.

As above stated, the exact distance the damper is located from, the pumpmay, vary, depending upon the character of the mixture being handled;however, I have found that distances ranging from 25 to 100 feet givesatisfactory results with all concrete mixtures now in common use whenpumping through a five inch discharge line.

It is obvious therefore that those skilled in the art may vary theprecise arrangement of the various instrumentalities without departingfrom the spirit of the invention, and it is not wished to be limited tothe details of the above disclosure. except as may be required by theclaims.

What is claimed is:-

, 1. The combination with a pump for concrete and similar plasticmaterials having valve controlled inlet and outlet passages which atcertain times in the operation of the pump may be simultaneously open,and a pulsation damping device, of longitudinally extended connectionsbetween said pump and device arranged to contain a quantity of thematerial being pumped sufiicient that the inertia thereof and thefriction between said material and the walls of said connections mayover-come the back pressure exerted by said damping device and preventbackslip of said material in said passages when they are simultaneouslyopen.

2. A pumping system for concrete and plastic materials havingcharacteristics similar thereto, comprising a pump having valvecontrolled inlet and outlet passages which at certain times in theoperation of the pump may be simultaneously open an amount sufiicient topermit of the plastic material flowing backward therethrough; adischarge conduit leading from said pump; and a pulsation damping devicecommunicating with said conduit at a distance from said pump sumcientthat the inertia and friction of the plastic material in said conduitbetween" the pump and the damping device may resist the back pressureexerted by the lattter to the extent necessary to prevent back-slip ofthe material through said passages when they are simultaneously open.

3. In a pumping system for concrete and plastic materials havingcharacteristics similar thereto, a pump having valve controlled passageswhich at certain times in the operation of the pump may besimultaneously open; a discharge conduit leading from said pump; and apulsation damping device communicating with said conduit at a distanceof at least twenty five feet from said pump, whereby the inertia andfriction of the mixture in said conduit between the pump and the dampingdevice may overcome the back pressure set up by the latter and preventback-slip of the mixture through said pump passages when they aresimultaneously open.

CHARLES F. BALL.

